ctu saturate (graphical LD twin)¶


suite id	`g_ctu_saturate`
domain	packaging
language	LD-graphical
difficulty	medium
validation status	candidate
origin	authored
license	CC-BY-4.0
syntax pair of	`ld_ctu_saturate`

Graphical twin of ld_ctu_saturate; the R pin is driven by a Reset contact

What is proved¶

From benchmarks/packaging/g_ctu_saturate/props.yaml. What each kind claims, and what it becomes on either route, is on The properties we prove.

id	kind	claim	requirement
`P1`	`invariant`	`!(Done && Reset)`	Reset is dominant: the count-up Done flag and Reset never hold together.

Variants¶

file	expected verdict	violates	method
`program.xml`	SAFE	none	expert

Files¶

file	what it is	size	sha256
`benchmark.yml`	benchmark metadata	0.7 KB	`e725e78aa5a2`
`program.xml`	ladder program, PLCopen XML	3.2 KB	`3863a4a3c74d`
`props.yaml`	property file	0.2 KB	`71301ff6f8f1`

Structured text, derived¶

Read off the ladder graph by runner/ld_to_st.py: every rung's contacts and coils rewritten as IEC 61131-3 assignments, in the same series/parallel logic the PLCopen XML encodes. This is a reading aid, not a second source of expected verdicts; ESBMC verifies the ladder program shown above, never this rendering.

program.xml

PROGRAM g_ctu_saturate
VAR_INPUT
    Pulse : BOOL;
    Reset : BOOL;
END_VAR

VAR_OUTPUT
    Done : BOOL;
END_VAR

VAR
    CTU0 : CTU;
END_VAR


CTU0(CU:=Pulse, PV:=2, R:=Reset);
Done := CTU0.Q;

END_PROGRAM

Recorded runs¶

A task can carry two routes. ld is ESBMC's ladder front end reading the program directly. via C is the same solver reached through Beremiz and MatIEC, which is the only route that reaches ST, IL, FBD and SFC; see How ESBMC-PLC works.

ctu_saturate (props.yaml, expected SAFE): master SAFE